albinism oculocutaneous type 3

(redirected from OCA3)

albinism oculocutaneous type 3

An autosomal recessive disorder (OMIM:203290) characterised by reduced synthesis of melanin pigment in skin, hair and eyes, despite normal tyrosinase activity. Darker-skinned individuals have bright copper-red colouration of skin and hair.

Ophthalmic findings
Red reflex on transillumination, dilution of iris colour, nystagmus and strabismus.
 
Molecular pathology
Defects of TYRP1 cause rufous oculocutaneous albinism and oculocutaneous albinism type 3.
References in periodicals archive ?
Prevalence rate of different genetic forms of OCA among the various world populations has determined OCA1 as the most widespread type of loci mapped among the Caucasian patients followed by OCA2 OCA4 and OCA3 respectively3.
Genetic analysis of families with inherited OCA so far has identified seven loci and six genes including; OCA1 (TYR) OCA2 (OCA2) OCA3 (TYRP1) OCA4 (SLC45A2) OCA5 OCA6 (SLC24A5) and OCA7 (C10orf11).
The third locus of oculocutaneous albinism OCA3 is positioned on long arm of chromosome 9 (9p23).
There are four major forms: (i) OCA1 (mutated tyrosinase (TYR) gene); [12] (ii) OCA2 (mutated OCA2 gene); [13] (iii) OCA3 (mutated tyrosinase-related protein 1 (TYRP1) gene); [14] and (iv) OCA4 (mutated solute carrier family 45, member 2 (SLC45A2) gene).
OCA3 (also known as rufous OCA) results from autosomal recessive mutations at the TYRP1 locus, at least in patients of African descent.
3 AR albinism OCA2 15q12--q13 AR OCA3 TYRP1 9p23 AR OCA4 MATP 5p13.
9p23 lokusundaki TYRP1 (tyrosinase-related protein 1) genindeki mutasyon sonucu gorulen OCA3 (tip 3) ve 5p'deki SLC45A2 (eski adiyla MATP) geninde resesif ozellikte mutasyon sonucu gorulen OCA4 nadir okulokutanoz albinizm tipleridir.